1. Field of the Invention
This invention relates generally to securing or anchoring devices and more particularly to devices used for securing, raising, or lowering objects with respect to spaced apart stationary surfaces of walls or beams or the like.
2. Description of the Prior Art
Various devices have been used to anchor or suspend objects from spaced apart members. While some of the devices rely on bolts or screws inserted into the members, others do not since it is frequently impractical to use such bolts or screws. For example, if a beam is made of steel or iron a bolt attachment requires tedious drilling. Even if the connection is to a wooden beam, drilling or inserting bolts is time consuming. Furthermore, if the connection is only temporary, the bolts are difficult to remove and leave permanent holes.
One variety of screwless and boltless securing devices has a pair of beam engaging ends which are moved apart and then held securely against opposing beams or the like. These devices are often very specific in their design and use. One of these is the chinning bar of the type connected in a door frame to provide a secure handhold for chinning exercises. Another is the hanger bar connected between closet walls to provide a receiver for clothes hangers. Other related or similar devices will be described below. Each of these prior art devices has a rigid connection and support member having on its ends two beam-engaging parts. The rigid connection and support member spans the gap between the opposing beams or walls to retain the engaging parts in connection with the beams or walls. It also serves to receive and support the retained object.
The chinning bar exemplifies the prior art. The chinning bar consists of a steel bar (connecting and support member) having two portions which are threaded together. At the outer ends of this bar are rubber discs (end members) adapted to resiliently engage a door frame. To mount the chinning bar, the threaded connection of the steel bar is adjusted by rotation to urge the rubber discs outwardly into resilient engagement with the door frame. Once it is securely mounted, chinning exercises can be performed by grasping a central portion of the bar and lifting the body relative to the bar. Other devices which have similar components are shown in U.S. Pat. Nos. 1,099,834; 2,713,983; 3,648,425; 3,892,378; 2,604,303; 3,049,328 and 3,281,107.
U.S. Pat. No. 1,099,834 discloses a compact fire escape which can be secured to a window frame. In operation, persons are lowered to the ground by a cable wound about a rotatable drum. The drum is secured to a wooden window frame by a pair of rods each of which is sharpened at its outer end to allow the end to pierce the window frame and be secured thereto. This allows the drum to be held between the window frame edges. The sharpened rods allow fast placement of the drum in an emergency.
U.S. Pat. No. 2,713,983 describes a bar used for supporting electrical outlet boxes. The bar has a threaded tubular portion with prongs on each end of the tube. When the tube threads are rotated the prongs move outwardly to engage, for example, attic joists. An electrical outlet box is connected to and supported by a midportion of the bar.
U.S. Pat. No. 3,648,425 depicts an adjustable bridging device for stabilizing floor joists. The device includes threaded telescoping portions adapted to engage the joists. One end of the device has two pointed prongs for engaging a joist such that one telescoping portion cannot rotate axially. The other end has a single central prong for penetrating a joist, allowing the telescoping member to rotate about the prong as it is inserted. Once in place, the telescoping members span and add stability to the joists.
U.S. Pat. No. 2,604,303 discloses a combined hoist and jack. The hoist is used to handle and brace timber, props, etc., in tunnels and mine shafts. The ends of the jack adjustably extend between the floor and the ceiling of the tunnel with prongs being provided on the upper end to engage the ceiling. A hoist pulley is attached to a central portion of the bar.
U.S. Pat. No. 3,049,328 discloses a cargo bracing device. The device consists of a pair of telescoped bars that extend into first contact with opposite walls of a cargo truck or vehicle. A rack and pinion gear operates to extend the bar.
U.S. Pat. No. 3,281,107 to Lewis depicts a hydraulic support prop including two ends which are caused hydraulically to move in opposite directions.
As can be seen, the prior art utilizes a central support bar which receives the entirety of the supported or secured weight in a manner which exerts a bending force on the bar. This requires the central bar to be doubly strong. First, it must have strength to hold the ends against the spaced apart beams or the like. Second, it must have strength to resist bending when a secured object is attached to the bar. For example, the chinning bar described above must be designed to urge its rubber disc end caps against a door frame hard enough to prevent the caps from slipping and the bar must not bend when a body weight is applied to the center of the bar. Consequently, the prior art securing devices can receive only a relatively small weight without the bar bending or breaking.
The devices in the past have attempted to overcome this problem by making the central bar stronger and, consequently, larger and heavier. Furthermore, the means for spreading and holding the ends of these devices to the spaced apart beams has been made more complex and bulky. The additional weight is itself a disadvantage. Moreover, complex and bulky devices often cannot be used in confined areas.
One particular situation where it is desirable to raise and lower heavy objects with respect to spaced apart wood beams is in an attic or basement. Often water heaters or air conditioners must be lifted or lowered with respect to the joists in the attic or basement. Usually there is no other convenient object to which the lifting or lowering means can be attached. In an attic or basement, the onfining and relatively restricted working space makes bulky or heavy devices unsuitably difficult to use. The objects are too heavy for normal, smaller securing bars. Consequently, securing heavy objects with respect to attic joists has, in the past been a tedious task, usually requiring bolts or screws or the like.